1. Field
Embodiments described in this specification relate to a buffer circuit disposed between an input/output pad and various kinds of circuits in a semiconductor integrated circuit.
2. Description of the Related Art
A semiconductor integrated circuit has a buffer circuit disposed between an input/output pad and various kinds of circuits. In a NAND cell type flash memory or the like, when a non-output-terminating interface specification is adopted to cut power consumption, it is important to suppress reflection (ringing) of an output signal at the output pad. In order to suppress ringing of an output signal, the slew rate of the output waveform must be lowered, but lowering of the slew rate is an obstacle to high-speed output.
On the other hand, it is required of this kind of buffer circuit that the slew rate be changeable in accordance with the specification and so on of the semiconductor integrated circuit. When adjusting the slew rate in this way, there is a problem that reflection (ringing) of output signal increases accordingly. Under the above circumstances, it is important for a buffer circuit that the slew rate of the output waveform thereof can be adjusted with a high degree of freedom.